The main topics are:
• Analyse of the different types of degradation and their mechanisms
• Indications for protective measures
• Selection of materials and techniques for rehabilitation
• Evaluation of operating conditions

The field of activities covers the behaviour of metallic and non metallic materials (concrete, plastics, bricks …).

History/Background

The European directive 91/271/EWG concerning the treatment of communal waste water, implemented in 1991, implicates that in many European countries a large number of sewage systems have to be constructed or rehabilitated. The goals and periods set in the mentioned directive were fulfilled so far only in few cases. Thus, for example, 110 of the 542 European large cities discharged their waste water still com-pletely or almost nearly untreated in the year 2001. Therefore it exists a large back-log demand for new waste water systems and the rehabilitation of old existing canali-sations, in which often strongly corrosive conditions prevail.
Experiences from Switzerland, where at the time of the implementation of the Euro-pean directive already approximately 90 % of the households were connected to waste water treatment plants, showed that often not enough attention is paid to the corrosion protection in sewage systems. In many plants this lead after three to eight years of operation to damages, whose repair caused high economical costs.
To avoid such damages and to give technical assistance to designers constructors and operators 1997 a working group has been formed in the sector B of CeoCor. Its main purpose was to elaborate a recommendation for corrosion protection in waste water installations. In the course of the work the originally planned topics have been extended by aspects of the inspection and rehabilitation, which on the one hand re-tarded the elaboration of the guidelines, on the other hand clearly showed, that in the field of waste water treatment there are many open questions and not or only partly solved problems concerning corrosion and the behaviour of different materials. This led 2004 to the decision to create in the CeoCor an own sector "waste water" (sector D).

Publications

Vol.1: (publication expected in Mai/June 2006)

1 Foreword
2 Result of a European Investigation
Classification and statistical analysis of corrosion problems
3 Description of a waste water system
Elements of waste water systems, canalisation, waste water plant
4 Corrosion in waste water systems
Aggressive environments, corrosion mechanisms for metals and concrete
Principles of corrosion protection
5 Corrosion induced by hydrogen sulphide
Formation of hydrogen sulphide, degradation mechanisms for metals and concrete, protective measures, remedial measures
6 Galvanic corrosion
Mechanism, corrosion rates, materials in danger, protective measures, remedial measures
7 Corrosivity of media present in waste water plants
Waste water, sludge, atmosphere, soil
8 From the inspection to an assessment of the structure
Inspection of waste water plants and canalisations, methodology, appearance of damages

Annexes

Vol. 2: (to be prepared)

9 Corrosion due to bad workmanship
10 Recommendations for the conception of waste water systems
11 Requirement Specifications
12 Rehabilitation

Annexes

Working Groups

D1: Corrosion and Corrosion Protection
Convenor: vacant
Interested persons: please contact the secretary or the president of the sector

This working group is elaborating the recommendation on corrosion protection in waste water systems (? publications).

Future work

As the sector D has started his work only in 2005 the future work is not yet defined in detail. The provisional programme of the sector contains the following activities:

• Publication of the recommendation “Corrosion and Corrosion protection in waste water systems” Vol. 1
• Elaboration of the recommendation “Corrosion and Corrosion protection in waste water systems” Vol. 2
• Presentation of the recommendation “Corrosion and Corrosion protection in waste water systems”
• Search for members
• Enquiry for working items and working groups
• Elaboration of more detailed work program
• Creation of new working groups